WWROF Webinar - Apr 2014 - K9LA WWROF Webinar - Apr 2014 - K9LA Are We Headed Into Another Are We Headed Into Another Maunder Minimum? Maunder Minimum? And If That Happens, What And If That Happens, What Does That Mean For Does That Mean For Propagation? Propagation? Carl Luetzelschwab K9LA Carl Luetzelschwab K9LA [email protected] (e-mail) [email protected] (e-mail) http://k9la.us (web site) http://k9la.us (web site)
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WWROF Webinar - Apr 2014 - K9LA Are We Headed Into Another Maunder Minimum? And If That Happens, What Does That Mean For Propagation? Carl Luetzelschwab.
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TopicsTopics Quick Update on Cycle 24Quick Update on Cycle 24 What is a Grand Solar Minimum?What is a Grand Solar Minimum? Quick review of the Maunder MinimumQuick review of the Maunder Minimum Review of solar parameters pertaining to Review of solar parameters pertaining to
Grand Solar Minimums and Maunder Grand Solar Minimums and Maunder MinimumsMinimums
Propagation during a Grand Solar Propagation during a Grand Solar MinimumMinimum• Scenario 1 (VOACAP with zero sunspots)Scenario 1 (VOACAP with zero sunspots)• Scenario 2 (deeper look at EUV)Scenario 2 (deeper look at EUV)
Great propagation on higher bands in late 2011 & late 2013Great propagation on higher bands in late 2011 & late 2013• High monthly means in fall/winter monthsHigh monthly means in fall/winter months• Annual change in the atmosphere’s composition – best for ion Annual change in the atmosphere’s composition – best for ion
production in fall/winter/spring monthsproduction in fall/winter/spring months Latest activity will extend good propagation to late 2014Latest activity will extend good propagation to late 2014
Cycle 24 in terms of 10. 7 cm solar flux
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24 data points aren’t a lot, but the 24 data points aren’t a lot, but the cyclic trend suggests we are entering cyclic trend suggests we are entering a third period of small solar cyclesa third period of small solar cycles
What Is A Grand Solar Minimum?What Is A Grand Solar Minimum?A Grand Solar Minimum is a period of A Grand Solar Minimum is a period of at least several solar cycles that are of at least several solar cycles that are of less-than-average magnitudeless-than-average magnitude
Earlier Grand Solar MinimumsEarlier Grand Solar Minimums
At solar min, the Sun’s At solar min, the Sun’s weak magnetic field weak magnetic field allows more cosmic rays allows more cosmic rays (CRs) into the Earth’s (CRs) into the Earth’s atmosphereatmosphere
Secondary particles Secondary particles created from collisionscreated from collisions
1010Be in ice cores, Be in ice cores, 1414C in C in tree ringstree rings
Out-of-phase with solar Out-of-phase with solar cyclecycle
High High 1010Be and Be and 1414C C indicates low solar indicates low solar activityactivity
Maunder Minimum had few sunspotsMaunder Minimum had few sunspots Recent GSMs had fair amount of sunspotsRecent GSMs had fair amount of sunspots We’ve assumed the Maunder Min was an extreme GSMWe’ve assumed the Maunder Min was an extreme GSM
• Maybe it isn’t an extreme GSM – maybe it’s a different processMaybe it isn’t an extreme GSM – maybe it’s a different process
Many Articles on Maunder MinMany Articles on Maunder Min Feynman and Ruzmaikin, 2011, Solar PhysicsFeynman and Ruzmaikin, 2011, Solar Physics
• Created criteria for Maunder-type Min vs Gleissberg Created criteria for Maunder-type Min vs Gleissberg cyclecycle
• What we’re seeing is not a Maunder-type MinimumWhat we’re seeing is not a Maunder-type Minimum Svalgaard, 2012, Nobeyama dataSvalgaard, 2012, Nobeyama data
• Maunder Min not due to lack of observations Maunder Min not due to lack of observations • Not a deficit of magnetic flux, but lessening of efficiency Not a deficit of magnetic flux, but lessening of efficiency
of the process that compacts magnetic fields into visible of the process that compacts magnetic fields into visible spotsspots
• May be happening again (see ‘disappearing sunspots’)May be happening again (see ‘disappearing sunspots’) Steinhilber and Beer, 2013, JGRSteinhilber and Beer, 2013, JGR
• Predict a period of low activity until 2100Predict a period of low activity until 2100 Hathaway, 2013, Huntsville HamfestHathaway, 2013, Huntsville Hamfest
• Cycle 24 smallest in 100 yearsCycle 24 smallest in 100 years• Cycle 25 may be smallerCycle 25 may be smaller
Articles – continuedArticles – continued McCracken and Beer, 2014, JGRMcCracken and Beer, 2014, JGR
• 2006-2009 CR intensities not as great as prior GSMs2006-2009 CR intensities not as great as prior GSMs Vaquero, et al, 2011, Astrophysical Journal lettersVaquero, et al, 2011, Astrophysical Journal letters
• Three descending cycles prior to Maunder MinThree descending cycles prior to Maunder Min Giampapa, 2014, Forbes on-lineGiampapa, 2014, Forbes on-line
• Cites hemispheric asymmetry in sunspots, weakening of Cites hemispheric asymmetry in sunspots, weakening of polar magnetic fields and decline in sunspots’ magnetic polar magnetic fields and decline in sunspots’ magnetic field strengthfield strength
Livingston and Penn, 2009, EOS (AGU weekly Livingston and Penn, 2009, EOS (AGU weekly newsletter)newsletter)• Sunspots are disappearingSunspots are disappearing
Altrock, 2012, AFRLAltrock, 2012, AFRL• ‘‘Rush to the Poles’ (from Fe XIV emission data) slow and Rush to the Poles’ (from Fe XIV emission data) slow and
intermittent for Cycle 24intermittent for Cycle 24
Maunder Min vs Gleissberg CycleMaunder Min vs Gleissberg Cycle
Maunder-type MinimumMaunder-type Minimum• Duration from 20 – 190 yearsDuration from 20 – 190 years• Distributed randomly in timeDistributed randomly in time• Onset can be abrupt or follow a few decreasing solar Onset can be abrupt or follow a few decreasing solar
cyclescycles• Sunspot number extremely lowSunspot number extremely low• Galactic CRs highGalactic CRs high• Mid-latitude aurora extremely rareMid-latitude aurora extremely rare
Gleissberg CycleGleissberg Cycle• Period of 90-100 yearsPeriod of 90-100 years
About eight 11-year solar cyclesAbout eight 11-year solar cycles• Maximum sunspot numbers below average, but not zero Maximum sunspot numbers below average, but not zero • Sunspot number returns to nearly same low value at 11-Sunspot number returns to nearly same low value at 11-
Based on 9400 years of spectral Based on 9400 years of spectral analysis of analysis of 1010Be (ice core) and Be (ice core) and 1414C C (tree ring) records(tree ring) records
Assumes the Sun will continue to Assumes the Sun will continue to vary with the same periodicities for vary with the same periodicities for the next centuriesthe next centuries
In his presentation at the 2013 Huntsville In his presentation at the 2013 Huntsville Hamfest, Dr. Hathaway said Cycle 25 may Hamfest, Dr. Hathaway said Cycle 25 may be even smaller than Cycle 24be even smaller than Cycle 24
This is based on decreasing polar fieldsThis is based on decreasing polar fields• See later ‘Polar Magnetic Fields’ slideSee later ‘Polar Magnetic Fields’ slide
He prefaced his presentation with the He prefaced his presentation with the following on his second slidefollowing on his second slide
Three Descending CyclesThree Descending Cycles Vaquero, Gallego, Vaquero, Gallego,
Usoskin, Kovaltsov Usoskin, Kovaltsov reviewed old data and reviewed old data and used newly-found data used newly-found data prior to Maunder Minprior to Maunder Min• Their work is in The Their work is in The
They concluded that They concluded that Cycle -9 was not as high Cycle -9 was not as high as earlier thought (due to as earlier thought (due to sparse amount of data)sparse amount of data)• Cycle -11 with Rg about 120Cycle -11 with Rg about 120• Cycle -10 with Rg about 35Cycle -10 with Rg about 35• Cycle -9 with Rg about 20 (originally thought to be about 80)Cycle -9 with Rg about 20 (originally thought to be about 80)
These three descending cycles preceded the Maunder These three descending cycles preceded the Maunder MinimumMinimum
We’re seeing three descending cycles now – even four!We’re seeing three descending cycles now – even four! Perhaps three descending cycles indicates a Maunder-type Perhaps three descending cycles indicates a Maunder-type
Minimum as opposed to Dalton-type minimumMinimum as opposed to Dalton-type minimum
When the field is about to enter a When the field is about to enter a grand minimum or is leaving a grand grand minimum or is leaving a grand minimum, we see more sunspots in minimum, we see more sunspots in one solar hemisphere than the otherone solar hemisphere than the other• From Steve Tobias (applied From Steve Tobias (applied
mathematician at the University of mathematician at the University of Leeds (UK)Leeds (UK)
The Sun’s polar magnetic fields are much weaker nowThe Sun’s polar magnetic fields are much weaker now This plot shows the true 22-year cycle of the SunThis plot shows the true 22-year cycle of the Sun
We won’t see sunspots when strength less than 1500 GaussWe won’t see sunspots when strength less than 1500 Gauss Updated data still showing decreaseUpdated data still showing decrease But may be leveling offBut may be leveling off
““Rush to the Poles”Rush to the Poles” Horizontal axis is ‘time’, Horizontal axis is ‘time’,
vertical axis is ‘north solar vertical axis is ‘north solar latitude’latitude’
Data is yearly average Data is yearly average number of Fe XIV emission number of Fe XIV emission regions (530.3 nm) – kind regions (530.3 nm) – kind of like a butterfly diagramof like a butterfly diagram
Note the high latitude Note the high latitude ‘rush to the poles’ for ‘rush to the poles’ for Cycles 21, 22 and 23 – and Cycles 21, 22 and 23 – and the lack thereof for Cycle the lack thereof for Cycle 2424
Cycle max occurs when 76 Cycle max occurs when 76 +/-2 degrees is reached+/-2 degrees is reached
Cycle 24 significantly different from previous cyclesCycle 24 significantly different from previous cycles Northern hemisphere max in late 2011Northern hemisphere max in late 2011 Predicts southern hemisphere max in early 2014Predicts southern hemisphere max in early 2014
Predictions from ‘Rush to the Poles’Predictions from ‘Rush to the Poles’
Prediction: northern hemisphere late 2011 Prediction: northern hemisphere late 2011 Prediction: southern hemisphere early 2014Prediction: southern hemisphere early 2014
Cycle 24 in terms of 10. 7 cm solar flux
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Are We Headed Into A Maunder Are We Headed Into A Maunder Minimum?Minimum?
Most solar scientists believe we’re going to Most solar scientists believe we’re going to experience several low solar cyclesexperience several low solar cycles• In other words, a Grand Solar Minimum in the In other words, a Grand Solar Minimum in the
Gleissberg cycleGleissberg cycle But nothing bullet-proof to say we’re But nothing bullet-proof to say we’re
headed into a Maunder-type Minimumheaded into a Maunder-type Minimum We’ll have to “wait and see”We’ll have to “wait and see”
Zero sunspotsZero sunspots• Good low band propagationGood low band propagation• 17m F2 expected17m F2 expected• 15m F2 would be spotty15m F2 would be spotty• 12m and 10m F2 not likely12m and 10m F2 not likely• Es still expectedEs still expected
Let’s assume sunspots are disappearing per Let’s assume sunspots are disappearing per Livingston and PennLivingston and Penn
We have to remember that sunspots and 10.7 We have to remember that sunspots and 10.7 cm solar flux are proxies for the true ionizing cm solar flux are proxies for the true ionizing radiation – which is EUV for the Fradiation – which is EUV for the F22 region region
What is happening to EUV?What is happening to EUV? Let’s go thru an exercise with sunspots and Let’s go thru an exercise with sunspots and
10.7 cm solar flux10.7 cm solar flux Then we’ll go through an exercise with EUV Then we’ll go through an exercise with EUV
It happened After Cycle 23 PeakIt happened After Cycle 23 Peak
Now data plotted only up to peak of Cycle 23Now data plotted only up to peak of Cycle 23 RR22 increased – correlation worse after Cycle 23 peak increased – correlation worse after Cycle 23 peak
Now let’s calculate what the Now let’s calculate what the sunspots should have been using sunspots should have been using the better correlation with 10.7 cm the better correlation with 10.7 cm solar flux in the previous slidesolar flux in the previous slide
Then we can plot these expected Then we can plot these expected values against what actually values against what actually happenedhappened
Sunspots Lower Than ExpectedSunspots Lower Than Expected
In light of Livingston and Penn data, 10.7 cm solar In light of Livingston and Penn data, 10.7 cm solar flux likely stayed constant and sunspots not as flux likely stayed constant and sunspots not as visiblevisible
But this does not address EUV yetBut this does not address EUV yet
EUVEUV Let’s go through the same exercise with 10.7 cm Let’s go through the same exercise with 10.7 cm
solar flux and 26-34 nm EUVsolar flux and 26-34 nm EUV 26-34 nm is responsible for about one half of all 26-34 nm is responsible for about one half of all
of the ionization in the Fof the ionization in the F22 region region Download data from SOHO 26-34 nm detectorDownload data from SOHO 26-34 nm detector Unfortunately we have less EUV data since we Unfortunately we have less EUV data since we
had to wait until we had satellites above the had to wait until we had satellites above the atmosphere to measure itatmosphere to measure it• EUV absorbed in the ionization process, so we can’t EUV absorbed in the ionization process, so we can’t
measure it at ground levelmeasure it at ground level
Assuming 10.7 cm solar flux is constant, EUV also decreased Assuming 10.7 cm solar flux is constant, EUV also decreased after the peak of Cycle 23 (but there was more of a delay)after the peak of Cycle 23 (but there was more of a delay)
Sunspots decreased to about 70% of expected valueSunspots decreased to about 70% of expected value EUV decreased to about 82% of expected valueEUV decreased to about 82% of expected value EUV may not be decreasing as much as sunspotsEUV may not be decreasing as much as sunspots
We need more EUV dataWe need more EUV data In other words, all of this is speculation – In other words, all of this is speculation –
caveat emptorcaveat emptor But maybe a Maunder Minimum won’t be But maybe a Maunder Minimum won’t be
as bad as we think if the EUV doesn’t as bad as we think if the EUV doesn’t decrease as much as sunspotsdecrease as much as sunspots• 15m F2 moves from “spotty” to “good”15m F2 moves from “spotty” to “good”• 12m and 10m may have F2 openings12m and 10m may have F2 openings
SummarySummary Something inside the Sun appears to have changed around Something inside the Sun appears to have changed around
the peak of Cycle 23the peak of Cycle 23
There’s lots of evidence that we are entering a Grand Solar There’s lots of evidence that we are entering a Grand Solar MinimumMinimum
But nothing 100% sure to say it’s going to be a Maunder-But nothing 100% sure to say it’s going to be a Maunder-type Minimumtype Minimum
If it is a Maunder-type Minimum, 15m F2 will be spotty, with If it is a Maunder-type Minimum, 15m F2 will be spotty, with no 12m and 10m F2 and only 6m Esno 12m and 10m F2 and only 6m Es
If it is a Dalton-type Minimum, we’ll experience propagation If it is a Dalton-type Minimum, we’ll experience propagation kind of like what we’re experiencing nowkind of like what we’re experiencing now
We’re going to collect some good data in the next ten years We’re going to collect some good data in the next ten years or so to hopefully explain what the Sun is doing and how it or so to hopefully explain what the Sun is doing and how it impacts a Grand Solar Minimumimpacts a Grand Solar Minimum
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